Revert caching in favor of simple ttl

Kubernetes-commit: 1122091b065b5ce37a93b1048174acaff243bf74

applyconfigurations/meta/v1/unstructured.go

@@ -58,17 +58,14 @@ func (c *gvkParserCache) objectTypeForGVK(gvk schema.GroupVersionKind) (*typed.P
 	c.mu.Lock()
 	defer c.mu.Unlock()
 	// if the ttl on the openAPISchema has expired,
-	// recheck the discovery client to see if the Open API schema has changed
+	// regenerate the gvk parser
 	if time.Now().After(c.lastChecked.Add(openAPISchemaTTL)) {
 		c.lastChecked = time.Now()
-		if c.discoveryClient.HasOpenAPISchemaChanged() {
-			// the schema has changed, regenerate the parser
-			parser, err := regenerateGVKParser(c.discoveryClient)
-			if err != nil {
-				return nil, err
-			}
-			c.gvkParser = parser
+		parser, err := regenerateGVKParser(c.discoveryClient)
+		if err != nil {
+			return nil, err
 		}
+		c.gvkParser = parser
 	}
 	return c.gvkParser.Type(gvk), nil
 }

discovery/cached/disk/cached_discovery.go

@@ -240,11 +240,6 @@ func (d *CachedDiscoveryClient) OpenAPISchema() (*openapi_v2.Document, error) {
 	return d.delegate.OpenAPISchema()
 }
 
-// HasOpenAPISchemaChanged checks wether the open API schema being served is cached or not.
-func (d *CachedDiscoveryClient) HasOpenAPISchemaChanged() bool {
-	return d.delegate.HasOpenAPISchemaChanged()
-}
-
 // Fresh is supposed to tell the caller whether or not to retry if the cache
 // fails to find something (false = retry, true = no need to retry).
 func (d *CachedDiscoveryClient) Fresh() bool {

discovery/cached/memory/memcache.go

@@ -149,10 +149,6 @@ func (d *memCacheClient) OpenAPISchema() (*openapi_v2.Document, error) {
 	return d.delegate.OpenAPISchema()
 }
 
-func (d *memCacheClient) HasOpenAPISchemaChanged() bool {
-	return d.delegate.HasOpenAPISchemaChanged()
-}
-
 func (d *memCacheClient) Fresh() bool {
 	d.lock.RLock()
 	defer d.lock.RUnlock()

discovery/discovery_client.go

@@ -121,15 +121,10 @@ type ServerVersionInterface interface {
 	ServerVersion() (*version.Info, error)
 }
 
-// OpenAPISchemaInterface has a method to retrieve the open API schema
-// and a method to check whether the open API schema has changed.
+// OpenAPISchemaInterface has a method to retrieve the open API schema.
 type OpenAPISchemaInterface interface {
 	// OpenAPISchema retrieves and parses the swagger API schema the server supports.
 	OpenAPISchema() (*openapi_v2.Document, error)
-
-	// HasOpenAPISchema changed checks whether the API schema being served
-	// by the apiserver is cached (and thus has not changed).
-	HasOpenAPISchemaChanged() bool
 }
 
 // DiscoveryClient implements the functions that discover server-supported API groups,
@@ -424,12 +419,6 @@ func (d *DiscoveryClient) ServerVersion() (*version.Info, error) {
 	return &info, nil
 }
 
-// HasOpenAPISchemaChanged checks whether a HEAD request to openapi endpoint returns
-// a 304 StatusNotModified meaning it has not changed.
-func (d *DiscoveryClient) HasOpenAPISchemaChanged() bool {
-	return !d.restClient.Verb("HEAD").AbsPath("/openapi/v2").SetHeader("Accept", mimePb).Do(context.TODO()).FromCache()
-}
-
 // OpenAPISchema fetches the open api schema using a rest client and parses the proto.
 func (d *DiscoveryClient) OpenAPISchema() (*openapi_v2.Document, error) {
 	data, err := d.restClient.Get().AbsPath("/openapi/v2").SetHeader("Accept", mimePb).Do(context.TODO()).Raw()

discovery/fake/discovery.go

@@ -153,11 +153,6 @@ func (c *FakeDiscovery) OpenAPISchema() (*openapi_v2.Document, error) {
 	return &openapi_v2.Document{}, nil
 }
 
-// HasOpenAPISchemaChanged checks wether the open API schema being served is cached or not.
-func (c *FakeDiscovery) HasOpenAPISchemaChanged() bool {
-	return true
-}
-
 // RESTClient returns a RESTClient that is used to communicate with API server
 // by this client implementation.
 func (c *FakeDiscovery) RESTClient() restclient.Interface {

rest/request.go

@@ -1140,21 +1140,12 @@ func (r *Request) transformResponse(resp *http.Response, req *http.Request) Resu
 		}
 	}
 
-	// store the X-From-Cache header so that we can
-	// return it as part of the result
-	var fromCache bool
-	xFromCacheHeader, ok := resp.Header["X-From-Cache"]
-	if ok {
-		fromCache = len(xFromCacheHeader) == 1 && xFromCacheHeader[0] == "1"
-	}
-
 	return Result{
 		body:        body,
 		contentType: contentType,
 		statusCode:  resp.StatusCode,
 		decoder:     decoder,
 		warnings:    handleWarnings(resp.Header, r.warningHandler),
-		fromCache:   fromCache,
 	}
 }
 
@@ -1281,7 +1272,6 @@ type Result struct {
 	contentType string
 	err         error
 	statusCode  int
-	fromCache   bool
 
 	decoder runtime.Decoder
 }
@@ -1318,11 +1308,6 @@ func (r Result) Get() (runtime.Object, error) {
 	return out, nil
 }
 
-// FromCache returns whether the response was returned from the cache.
-func (r Result) FromCache() bool {
-	return r.fromCache
-}
-
 // StatusCode returns the HTTP status code of the request. (Only valid if no
 // error was returned.)
 func (r Result) StatusCode(statusCode *int) Result {